The 2022 World Cup attracted more than a million fans to Qatar. Fifa has been warned it is putting fans' health at risk by introducing a bottle ban at this summer's World Cup.

Fans will not be allowed to take reusable water bottles into World Cup stadiums due to safety concerns, Fifa said in a late policy change. The official stadium code of conduct previously stated: "For the avoidance of doubt, empty, transparent, reusable plastic bottles, up to (1 litre in) capacity, may be brought into the stadium." But seven days before the tournament kicks off on 11 June, bottles - along with cups, jars and cans - have been prohibited, with Fifa saying it will lower the risk of injury caused by fans throwing missiles.

"Fifa is committed to protecting the health and safety of all players, referees, fans, volunteers, and staff," football's world governing body said in a statement. Fans will be able to buy water in the stadium and Fifa has promised not to charge above their usual venue prices.

But heat experts have criticised the U-turn, with one saying the ban "will clearly heighten the risk of heat-related health incidents." In May, scientists warned that Fifa's heat safety measures for the tournament are "inadequate", as temperatures at 14 of the 16 host venues are set to exceed dangerous levels.

"Fifa works closely with each host city committee and local authorities on heat mitigation factors for fans travelling to the stadium, which can include resources such as misting stations, fans, hydration stations, cooling tents and more around the stadium footprint," Fifa's statement said. "Inside the stadium footprint, pricing for water bottles for the Fifa World Cup 2026 will remain consistent with other events held at each stadium."

The change in policy comes amid complaints that fans are being hit by "extortionate" ticket prices and inflated train fares. Fans were also prevented from taking bottles into stadiums at the last World Cup in Qatar. The Free Lions England fans' group called the move a "strange, late change." In a statement posted on X, it added: "In all of our discussions, free water availability in stadiums was a key one and we were assured by Fifa that this would be the case and that fans will have the ability to bring their own water bottle. "Naturally, the immediate thought from supporters is this is just the latest money-grab. For how hot the stadiums will be, many in open air, just let fans bring a bottle if they want to. "We hope the water fountains in stadiums will still be free, hopefully you aren't charged in the queue!"

Fifa has responded to heat safety concerns by introducing one three-minute hydration break in each half for every game at the tournament. But Ollie Jay, a professor of heat and health at the University of Sydney, says he is more worried about spectator welfare than that of players.

"If you look at the athlete population, all of them are very fit," Jay said. "Whereas if you think about the spectators, you've got a broad range of different people that will be attending, from young kids to elderly people, people with chronic diseases, people taking different types of medications - all of which results in different levels of heat sensitivity. Your average spectator is probably going to be less resilient to the heat than these highly-conditioned professional athletes."

He warned that heat strain could accumulate progressively as fans are exposed to heat on their journey to the game and risk arriving at the stadium in a state of dehydration. "It's not just the temperature that we need to be concerned about," Jay added. "If you think about your average spectator sitting in a closely confined area surrounded by lots of other people, they'll be in direct sunlight. It might be humid. The airflow might be low. And therefore, the amount of heat stress that their body has to cope with could be quite significant."

In May, Jay was one of 20 experts who signed an open letter to Fifa warning that guidelines left players at risk of serious harm. Plans for misting systems and shaded areas were called "inadequate" - and Jay says that the bottle ban endangers fans further: "Unless the cooling controls are really successful, I would imagine this decision [to ban water bottles in stadiums] will clearly heighten the risk of heat-related health incidents."

Dr Theodore Keeping from Imperial College London, author of a World Weather Attribution study of heat safety at the tournament, stressed the importance of access to water. "Allowing fair and equitable access to hydration is a basic first defence against the extreme heat risks climate change is bringing to this World Cup," Keeping said.

Andrew Simms, from the New Weather Institute, said: "Is Fifa climate-trolling the game it's meant to protect? It is already staging the most polluting World Cup ever, sponsored by one of the world's biggest climate-polluting oil companies, and has heat safety protocols heavily criticised by world leading health experts. Now making it even more difficult for fans to stay safe in a competition vulnerable to global heating seems to be a reckless rejection of Fifa's duty of care."

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